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Slit-Beam Ruler
802
AMERICAN JOURNAL OF OPHTHALMOLOGY
tal. His lectures on muscles and plastic surgery left his students breathless. Dr. Spaeth's major interest was in plastic sur gery and he was one of the founders of the American Board of Plastic Surgery. Dr. Spaeth received numerous awards and special citations. He was also consultant to numerous hospitals and his services and opinions were the basis for forming a Plastic Service at the Wills Eye Hospital where he was active until the last four or five years of his life. Besides his professional attainments which are recorded in our professional references there was another side of his life of which few people were aware. I first met Dr. Spaeth in 1936. At that time he was busy writing his well-known text book, "Principles and Practice of Oph thalmic Surgery." An invitation for din ner was of a personal nature—one or two guests—with dinner served by his charm ing and delightful wife, Lea, a bedtime story for his two young sons, and then to the library. Dr. Spaeth had many extracurricular interests and activities. He used to fence regularly and at one time he was Sabre Champion of Pennsylvania. H e had a pro found interest in astronomy and had a large library on this subject. He was a great forester having his own tree farm and being Forester to Squirrel Island, Maine, where he spent his summers. He belonged to the East Hill Hunting Club in Williamsport, not so much to hunt, but to see the deer, bears, turkeys, and to be with nature. He was an excellent fisher man adhering only to fly-fishing. Another of his great passions was music—he had a Saturday evening box at the Academy of Music in Philadelphia, never missed a concert of the Philadel phia Orchestra, traveled to New York for the opera, and spent summers at the Salsburg and Wagnerian festivals. He had a remarkable memory and could tell Lea
NOVEMBER, 1976
when they first heard the concert or opera, who conducted, and who were the princi pals. Ned Spaeth left a significant contribu tion to ophthalmology, but his family and his grandchildren are an even greater con tribution. Philip and George are ophthal mologists, and Karl and Edmund, Jr., are lawyers, the latter one of the most respect ed judges in the Commonwealth of Penn sylvania. Dr. Spaeth led a full life. His pace at times was hectic, but this was always tempered by his kind, understanding, and sympathetic wife. He can well be satis fied with the legacy he has left in his wife, his sons, grandchildren, and his host of friends. P. R O B B M C D O N A L D
CORRESPONDENCE Letters to the Editor must be typed double-spaced on 8V2 x 11-inch bond paper, with 1'/2-inch margins on all four sides, and limited in length to two manuscript pages.
Slit-Beam Ruler Editor: In their paper, "Slit-beam ruler," Mi chael A. Callahan and Samuel J. Kimura (Am. J. Ophthalmol. 81:851, 1976) com mented on the usefulness of the HaagStreit Model 900 Calibrated slit-beam ruler. Peter Laibson has long emphasized such accurate measurements of corneal lesions by this method. However, because this slit ruler is calibrated in approxi mately 2 mm intervals, it provides only an estimate of the lesion's size. More ad vantageous is the slit of infinitely var-
VOL. 82 NO. 5
803
CORRESPONDENCE
encouraging precision in biomicroscopic observation. G E O R G E O. W A R I N G ,
Davis,
M.D.
California
Reply
Infinitely variable Haag-Streit Model 900 slitbeam ruler. Knurled knob (black arrow) adjusts slit height to size indicated on ruler (white arrows).
iable height, available on Haag-Streit Model 900 slit lamps after No. 12840, which allows more accurate measurement (Figure). I have often found it difficult to mea sure precisely the distance of a lesion from the corneoscleral limbus (for exam ple, the size of a pterygium or the distance a vessel has extended into the cornea), because the corneoscleral limbus is not a precise reference point. A conjunctival vessel with an obvious branching near the corneoscleral limbus serves as a reliable fixed reference point when identified by a brief sketch in the chart, and provides precise orientation for repeated measure ments by multiple observers. Drs. Callahan and Kimura have done a service by
It would have been presumptuous not to think that other clinicians were using the slit beam as a ruler. Our only purpose in publishing the technique, which has been taught and used in our department for many years, was to bring it to the attention of clinicians who were not aware of this added use of a biomicro scope. We agree with Dr. Waring that the newer Haag-Streit Model 900 slit-lamp microscope with ä micrometer is more convenient. However, most people proba bly do not have this model, and it isn't really necessary. The same observer makes the same estimate using slits cali brated at 2 mm intervals. We also agree that pterygium s are often difficult to mea sure accurately. We believe, however, that the slit-beam ruler is as accurate as a photograph and a lot more convenient. S A M U E L J. KIMURA,
San Francisco,
M.D.
California
Incandescent and Fluorescent Light Sources Editor: The recent article, "Light intensity oh the photodynamic inactivation of herpes simplex keratitis" (Am. J. Ophthalmol. 81:332,1976), shed some light on an alter nate method of treatment of this viral keratitis. However, the evaluation of in candescent light was not comparable to that of the two fluorescent sources. The energy density received by the treated corneas is equal to the radiant strength of the source, multiplyed by a
AMERICAN JOURNAL OF OPHTHALMOLOGY
tal. His lectures on muscles and plastic surgery left his students breathless. Dr. Spaeth's major interest was in plastic sur gery and he was one of the founders of the American Board of Plastic Surgery. Dr. Spaeth received numerous awards and special citations. He was also consultant to numerous hospitals and his services and opinions were the basis for forming a Plastic Service at the Wills Eye Hospital where he was active until the last four or five years of his life. Besides his professional attainments which are recorded in our professional references there was another side of his life of which few people were aware. I first met Dr. Spaeth in 1936. At that time he was busy writing his well-known text book, "Principles and Practice of Oph thalmic Surgery." An invitation for din ner was of a personal nature—one or two guests—with dinner served by his charm ing and delightful wife, Lea, a bedtime story for his two young sons, and then to the library. Dr. Spaeth had many extracurricular interests and activities. He used to fence regularly and at one time he was Sabre Champion of Pennsylvania. H e had a pro found interest in astronomy and had a large library on this subject. He was a great forester having his own tree farm and being Forester to Squirrel Island, Maine, where he spent his summers. He belonged to the East Hill Hunting Club in Williamsport, not so much to hunt, but to see the deer, bears, turkeys, and to be with nature. He was an excellent fisher man adhering only to fly-fishing. Another of his great passions was music—he had a Saturday evening box at the Academy of Music in Philadelphia, never missed a concert of the Philadel phia Orchestra, traveled to New York for the opera, and spent summers at the Salsburg and Wagnerian festivals. He had a remarkable memory and could tell Lea
NOVEMBER, 1976
when they first heard the concert or opera, who conducted, and who were the princi pals. Ned Spaeth left a significant contribu tion to ophthalmology, but his family and his grandchildren are an even greater con tribution. Philip and George are ophthal mologists, and Karl and Edmund, Jr., are lawyers, the latter one of the most respect ed judges in the Commonwealth of Penn sylvania. Dr. Spaeth led a full life. His pace at times was hectic, but this was always tempered by his kind, understanding, and sympathetic wife. He can well be satis fied with the legacy he has left in his wife, his sons, grandchildren, and his host of friends. P. R O B B M C D O N A L D
CORRESPONDENCE Letters to the Editor must be typed double-spaced on 8V2 x 11-inch bond paper, with 1'/2-inch margins on all four sides, and limited in length to two manuscript pages.
Slit-Beam Ruler Editor: In their paper, "Slit-beam ruler," Mi chael A. Callahan and Samuel J. Kimura (Am. J. Ophthalmol. 81:851, 1976) com mented on the usefulness of the HaagStreit Model 900 Calibrated slit-beam ruler. Peter Laibson has long emphasized such accurate measurements of corneal lesions by this method. However, because this slit ruler is calibrated in approxi mately 2 mm intervals, it provides only an estimate of the lesion's size. More ad vantageous is the slit of infinitely var-
VOL. 82 NO. 5
803
CORRESPONDENCE
encouraging precision in biomicroscopic observation. G E O R G E O. W A R I N G ,
Davis,
M.D.
California
Reply
Infinitely variable Haag-Streit Model 900 slitbeam ruler. Knurled knob (black arrow) adjusts slit height to size indicated on ruler (white arrows).
iable height, available on Haag-Streit Model 900 slit lamps after No. 12840, which allows more accurate measurement (Figure). I have often found it difficult to mea sure precisely the distance of a lesion from the corneoscleral limbus (for exam ple, the size of a pterygium or the distance a vessel has extended into the cornea), because the corneoscleral limbus is not a precise reference point. A conjunctival vessel with an obvious branching near the corneoscleral limbus serves as a reliable fixed reference point when identified by a brief sketch in the chart, and provides precise orientation for repeated measure ments by multiple observers. Drs. Callahan and Kimura have done a service by
It would have been presumptuous not to think that other clinicians were using the slit beam as a ruler. Our only purpose in publishing the technique, which has been taught and used in our department for many years, was to bring it to the attention of clinicians who were not aware of this added use of a biomicro scope. We agree with Dr. Waring that the newer Haag-Streit Model 900 slit-lamp microscope with ä micrometer is more convenient. However, most people proba bly do not have this model, and it isn't really necessary. The same observer makes the same estimate using slits cali brated at 2 mm intervals. We also agree that pterygium s are often difficult to mea sure accurately. We believe, however, that the slit-beam ruler is as accurate as a photograph and a lot more convenient. S A M U E L J. KIMURA,
San Francisco,
M.D.
California
Incandescent and Fluorescent Light Sources Editor: The recent article, "Light intensity oh the photodynamic inactivation of herpes simplex keratitis" (Am. J. Ophthalmol. 81:332,1976), shed some light on an alter nate method of treatment of this viral keratitis. However, the evaluation of in candescent light was not comparable to that of the two fluorescent sources. The energy density received by the treated corneas is equal to the radiant strength of the source, multiplyed by a